General manager Martin Mayhew tabbed the Nebraska product in the second round (54th overall) because he lost his former starting running back. Naturally, this led to comparisons to the now-49er, and it's legitimate from a role perspective, but these two are distinctly different players.
We all remember Bush for what he was—a quick player with too many east-west tendencies. He could make four guys miss and take the corner for 60 yards, but he too often would pick up dramatically more laterally than vertically.
So who is Ameer Abdullah?
Abdullah, the Strong Scat Back
The misconception that Abdullah and Bush are the same player come from their "burstability.